As medical diagnostic imaging equipment that can conduct functional diagnosis on body tissue of a subject, a positron emission computed tomography apparatus (PET apparatus) has been known. Specifically, in a PET exam, a medicinal agent labeled with positron emitting radionuclides is administered to a subject. Then, the PET apparatus detects a pair of 511 keV gamma rays that are emitted in substantially opposite directions when positrons emitted from the medicinal agent are bound to electrons to disappear, and thereby reconstructs an image (PET image) that indicates distribution of the tissue of the subject that has taken the medicinal agent.
More specifically, the PET apparatus performs coincidence counting on a pair of 511 keV gamma rays that are emitted in substantially opposite directions, by use of a detector that is formed of photon-counting detector modules arranged around the subject in the form of a ring. Then, the PET apparatus performs operation processing on the coincidentally counted gamma ray data (coincidence counting information) to reconstruct a PET image.
The conventional PET apparatus, however, can store therein coincidence counting information generated by a coincidence counting circuit of a hardware structure only. In other words, because the conventional PET apparatus discards any output result of detector modules in which coincidence is not found, the apparatus cannot create coincidence counting information by changing coincidence counting parameters such as a time window width and an energy window width.
For this reason, in a conventional PET apparatus, a PET image has to be newly taken if image correction needs to be performed on a PET image at a request from a radiogram interpreter who interprets the PET image.